This invention relates to a screw press.
More particularly, this invention relates to a screw press for dewatering suspended fibrous pulp, the press being of the type comprising a perforated tubular casing and a rotatable screw member housed therein, said casing having an inlet and an outlet for the pulp, said outlet being devised to cooperate with a throttling member for generating a counter-pressure on advance feeding of the pulp in the casing. The throttling member may have the shape of a conical valve member which may be under the action of a pressure-producing member, such as a hydraulic servomotor, so as to cause the counter-pressure acting on the pulp to become adjustable and thereby adapted to impart to the pulp desired dry content. The throttling member producing the counter-pressure may be resilient so as gradually to open on start of the press until the predetermined dewatering pressure has been built up in the press.